Description of the Prior Art
U.S. patent application Ser. No. 520,322, filed Nov. 4, 1974, now U.S. Pat. No. 4,083,782, discloses a novel water conditioning process involving, inter alia, regeneration of the water treatment ion exchange resin.
The regeneration systems disclosed therein are the two step acid/alkali technique, and a one step method involving a solution of alkali metal salts of citric or fumaric acid with up to 10% sodium hydroxide. Sodium polyphosphate and sodium hexametaphosphate are also disclosed as regenerants.
In a residential environment, sodium hydroxide systems cause serious safety problems. Furthermore, alkali metal citrates and fumarates are relatively expensive.